There is an ongoing trend in the homesteading community where people choose to buy 50 or so chickens for the year to raise and then butcher for meet. This takes any where between 9 to 12 weeks depending on the breed before it is time to harvest them. Many choose to do things this way because they say that it is cheaper since you only raise them for a certain amount of time and because hybrids will not give you the same result if you breed them. This is similar to how most gardener grow heritage vegetables because they are true to the parent. Hybrids are mixed to you may only get certain traits from either parent.
But what about not relying on hatcheries? What about doing things the old fashioned way? Letting the chickens lay eggs and letting some of the eggs hatch. One issue with letting the hens go broody which means letting them sit on the eggs until they hatch, is that during that time they will stop laying eggs. So if you are looking to do this, you should probably have enough hens to continue the production of eggs.
Here is a video I found on maintaining your flock for the long term called “Dual Purpose Breed Chickens: A Flock Maintenance Plan” from Jassius Wise on YourTube.